Starting and operating circuit for fluorescent lamps



March 1, 1955 w. s. H. HAMILTON 2,703,375

STARTING AND OPERATING CIRCUIT FOR FLUORESCENT LAMPS 2 Sheets-Sheet 1Filed July 28, 1952 f m Y. i K 4 m mm m y m m 4 J a w m Wm 1 m u I a w'l c Q C 5 m .0 5 Q 2 r 4 m a I 0 .h I I W f 7 6 E Y w P I 1 L 9 8 In/ Br... 1

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STARTING AND OPERATING CIRCUIT FOR FLUORESCENT LAMPS mm July 28, 1952 2Sheets-Sheet 2 INVENTQR WILLIAM S. H. HAMILTON BY mam 2:4. Ma 'fl -J.

HIS ATTORNEYS circuit is .tion on either 2,703,375 Patented Mar. 1,1.955

STARTING AND OPERATING CIRCUIT FOR FLUORESCENT LAMPS William S. H.Hamilton, Larchmont, N. Y. Application July 28, 1952, Serial No. 301,2526 Claims. (Cl. 315-100) This invention relates to certain new and usefulimstarting and operating circuits for A. C. and D. C. fluorescent lamps,particularly long hot cathode A. C. fluorescent lamps, such as the 48",T-l2 ty in which the filamentary electrodcshave to ,be heated to Most ofth order for usev The present application is a continuation-in-part ofcorporation as Fig. l in this application. y

In the accompanying drawings I have shown certain new circuits forcarrying the present invention into practical effect, in which drawings:

Fig. 1 is a diagrammatic view of a for operation of lamps on A. C. andmy improved starter arrangement.

ig. 2 is a diagrammatic view of a circuit similar to Fig. 1 showing amodification in the construction.

Fig. 3 is a diagrammatic view showing the embodiment of the invention ina'circuit adapted for opera- A.C.or.D.C.

P Fig. 4 shows a modification of .the circuit shown in Referring nowmore particularly to Fig. 1 of the draw form of' circuit which embodies2 ing, 1 represents the gas containing envelope of the lamp having thefilamentary electrodes 2 and 3, and 4 and 5 are lamp operating and line,or

us connected across of this reactor-transwhlch is connected to From thesecondary 8 former leads a feed conductor 9 end of the filament 2,

being connected directly to the input end of filament 3, to the outputend of which is connected a conductor 25.

The branches 11, 12 are normally coupled by the automatically closingswitch member including a second ber 14 A condenser 13 is placed acrossthe contacts of switch by-pass branches 12 and heater 16 to and throughthe filament 3 and conductor 15' to and through the closed thermostaticcontacts 1718 of the starter 10 conductors 15 and 15 and switch terminal5. This provides for the fl short circuit the relay coil 15 beingenergized. When a sufiicient time has elapsed to heat the filaments ofthe lamp to the proper temperature, the thermostatic contacts 17-18 ofthe starter opened at the same time. current flows through the lamp andvia conductor 12' and through the relay coil 15 which holds the switches1314 open.

The switch 14 is arranged in series with the normally closedthermostatic contacts 17- 18 of the starter 10, so that when thecontacts 17-18 reclose, due to current being removed from the heater 16by the opening of switch 13, contacts 17-18 cannot reclose the s ortcircuit around relay coil 15, as switch 14 will be that the lamp willsoon fire. It should be understood that while the description has beenconfined to a particular type of lamp, the principle applies to any ofthe C. fluorescent lamps having filamentary electrodes. except those ofthe instant starttype (which are short lamp), and that the voltagesapplied would depend on the requirements of the lamp, transformer, orreactor.

If the lamp (Figure 1) does not fire on the first attempt, the starterwill make repeated attempts to start it, and if it does not succeed willshow by the continued applications and cutting off of the preheatingcurrent that the lamp is defective and should be replaced. This starterrequires the use of four leads.

As stated, the circuit of Fig. 1 provides a starter which overcomes thespecified objections to the glow switch type of starter and which ismore rugged and more cer tain and reliable in action and gives a signalglow in the lamp filaments immediately upon the line circuit beingclosed indicating that the lamp is in good order and should start withinits normal time period. The use of the circuit arrangement and relay ofFig. 1 also insures more accurate control of the circuit, less delay instarting a good lamp even hen a repeat action is necessary, and quickerrestarting actions when desired than is possible by the use of a glowswitch or a conventional type thermostatic starter.

Fig. 2 shows a circuit similar to that of Fig. l except for the use of asimple reactor actor-transformer 7, and the operation of Fig. 2 circuitis the same as that above described with relation to Fig. l circuit.Generally speaking, the two circuits are functionally equivalent thoughhaving difierent operating voltage of the A. C. line, the and the designof the reactorcharacteristics giving each a working advantage over theother under different working conditions.

Fig. 3 shows a circuit designed for the specific purpose of efiectingstarting of a lamp under low temperature conditions, i. e., F. andlower. it has the advantage that the starting current and the operatingcurrent can be separately adjusted. This enables a higher startingcurrent to be used than can be obtained from the ballast reactorordinarily used for a particular lamp, while at the same time permittingthe operating current to be adjusted to the proper current value afterthe lamp has fired. This circuit also allows a quick tion to be obtainedafter the lamp has been operating a few seconds and the line current hasbeen cut off and is again let on.

As shown, this circuit comprises containing a reactor 21 and leading tothe filament 2*, from one terminal of the other terminal of which leadsa return conductor 11 comprising a section 11 connected to one terminalof the filament 3 a section 11 connected to the line terminal 5, asection lit connected to the other terminal of filament 3 and a section11 arranged between the sections ll and the section 11. Section 11 has agap normally closed by a relay switch 13 and contains a current limitingresistor heater 16 Extending across the conductor sections 11 and 11 isa conductor ballast lamp 26 and current limiting resistance 8 formingpart of the operating circuit which is shunted 7 in place of thererestarting aca feed conductor 9,

l containing the relay coil or short circuited when the switch 14- andstarter contacts 24 are closed but which is connected in series with thelamp when the lamp is operating. Switches .13 14 and starter contacts 24when closed, establish a starting or preheating circuit ready foroperation when the line circuit is closed. The starter in this circuithas four terminals only, viz., x, y, x, y.

In this circuit in starting, current flows from one side of the line, orsupply, circuit, which may be a source of either alternating current ordirect current, through the reactor 21 through filament 2 of thefluorescent lamp, through the normally closed contacts of the relayswitch 13 through resistor 8*, to terminal of the starter. Thence thecurrent fiows through heater 16 to terminal x of the starter, throughthe other filament 3 of the fluorescent lamp, to terminal y of thestarter, through starter contacts 24 to terminal y of the starter,through the normally closed contacts of the relay switch 14 and thenceto the other side of the line or supply, circuit. During this preheatingaction, resistor 8 the ballast lamp 26 and relay coil 13* are shortcircuited by switch 14 and starter contacts 24 so that the relay coil15" is kept de-energized. The amount of preheating current can beadjusted by resistor 3 Preheating current continues of the starter heatsup the starter contacts 24 to cause them 'to 'open. When they open, theyremove sufficiently to flow until heater 16 I the short circuit aroundresistance 8, the ballast lamp '26 'a'nd coil 15" of the relay, thusenergizing the coil and causing the relay to open switches 13 and 14Switch 13 on opening,"'breaks the preheating circuit and causes thereactor to give an inductive kick to start the lamp. The lamp if innormal condition fires, an current flowing through the lamp flowsthrough resistor 8 the ballast lamp 26 and relay coil 15", thus keepingtherelay coil energized and switches 13 open. Switch 14 being openprevents the starter contacts 24 from reclosing the short circuit aroundresistance 8", the ballast lamp 26 and relay coil 15, when they recloseupon the cooling of heater 16 The operating currentcan'be adjusted toany desired value by the selection of the proper size-ballast lamp andthe proper resistance of resistor 8*.

The operating circuit is from one side of the line, through the reactor,to one filament of the fluorescent lamp, through the gas in the lampitself to the other filament, thence through resistance 8', the ballastlamp 26 and relay coil 15 to the other side of the line.

If the line circuit is opened while the lamp is operating, the relaycoil IS -Will be de-energized and allow switches 13 and 14 to recloseimmediately, ready for another starting action. As long as the lamp hasoperated along enough for the contacts 24 of the starter to reclose(which is only a few seconds), this circuit is always ready for astarting or restarting action, and there will be a glow in bothfilaments as soon as the line circuit is closed.

Fig. 4 shows a circuit which is similar in all respects to Fig. 3 withthe following exceptions: the inductive reactance device 21, instead ofbeing connected in the feed conductor 9 to filament 2 is connected inthe opposite side of the line, namely, in feed conductor ll" from theline terminal 5. Also in Fig. 4 the diagrammatic illustration of thefour contact pins x, y and x, y has been omitted. Finally, the currentcontrolling resistance 8 is omitted, the operating current beingcontrolled entirely by the ballast lamp.

If the lamp (Figure 3) does not fire on the first attempt, the starterwill make repeated attempts to restart it, and if it does not succeedwill show by its con tinued applications and removal of current that thelamp is defective and should be replaced. The starter in this circuitrequires the use of four leads.

Practical use of the starter organizations herein disclosed has shownthat the starter relay circuits work with greater efficiency thanordinary starters, and will fire lamps which glow switch starters andother thermostatic starters will not fire, due to the rapid breaking ofthe preheating circuit by the relay contacts which is much more rapidthan is obtained by any of the starters now generally employed. Thisprevents the troubles and annoyances often caused in starting lamps,particularly those of the type described, in using the glow switch typeof starter and other starters.

it will be understood, of course, that while i have shown certain waysof carrying my invention into practical effect, other ways or meansequivalent thereto, and falling within the scope of the appended claims,may be employed without departing from the spirit of my invention. Itwill also be understood that while I have set forth the disadvantages ofcircuits using straight thermal and glow switch types of starters ashereinbefore constructed and used, and the advantages attained by theuse of a thermostatic type of starter, I. do not limit myself to theuse, except when specified in the claims, to any particular type ofstarter or time delay device which may be used to carry my inventioninto practical eflect.

What is claimed is:

1. In combination, a gaseous electric discharge device having twoelectrodes constructed to receive preheating current, a supply circuit,a relay having an operating coil and two sets of normally closedcontacts, means including an inductive reactance device and theoperating coil of said relay for connecting said electrodes to saidsupply circuit. a delay device having an operating circuit and normallyclosed contacts, and an electrode preheating circuit capable ofproducing firing temperature electrode heating, said circuit extendingfrom one side of a voltage source to the opposite side of said sourceand including in series connection said inductive reactance device, saidtwo electrodes, one set of relay contacts, said delay device operatingcircuit and a circuit connected in shunt with said relay switchoperating coil, said shunt circuit including in series connection thecontacts of said delay device and the second set of relay contacts sothat the opening of said delay contacts causes the energization of saidoperating coil and the consequent opening of said sets of relaycontacts, the opening of said first set causing the discharge device tofire by an inductive voltage kick, said first set of contacts beingconnected in shunt with said electrodes, and the opening of the secondset of relay contacts maintaining said operating coil energized afterthe delay device contacts have reclosed.

2. The combination set forth in claim 1 in which the delay device is athermostatic switch having a heating circuit and normally closedcontacts, the said heating circuit being included in series connectionwith the electrode preheating circuit.

3. The combination set forth in claim 1 in which one of the electrodesis connected to one side of the supply circuit through a circuitincluding an inductive reactance device, and the other electrode isconnected to the opposite side of the supply circuit through a circuitincluding the operating coil of the relay.

4. In combination a gaseous electric discharge device having first andsecond electrodes constructed to receive preheating current, a supplycircuit, a relay having two sets of normally closed contacts, meansincluding an inductive reactance device and the opera-ting coil of saidrelay for connecting said electrodes to said supply circuit, a delaydevice having an operating circuit and normally closed contacts, and anelectrode preheating circuit capable of producing firing temperatureelectrode heating, said circuit extending from one side of a voltagesource to the opposite side of said source and including in seriesconnection said inductive reactance device, and in sequence the firstelectrode, one set of relay contacts, said delay device operatingcircuit, the second electrode and a circuit connected in shunt with saidrelay switch operating coil, said shunt circuit including in seriesconnection the contacts of said delay device and the second set of relaycontacts so that the opening of said delay contacts causes theenergization of said operating coil and the consequent opening of saidsets of relay contacts, the opening of said first set causing thedischarge device to fire by an inductive voltage kick, said first set ofsaid contacts being connected in shunt with said electrodes, and theopening of the second set of relay contacts maintaining said operatingcoil energized after the delay device contacts have reclosed.

' having first and second electrodes constructed to receive preheatingcurrent, a supply circuit, a relay having an operating coil and two setsof normally closed contacts, means including an inductive reactancedevice and the operating coil of said relay for connecting saidelectrodes to said supply circuit, a current controlling deviceconnected in series with said coil, a delay device having an operatingcircuit and normally closed contacts, and an electrode preheatingcircuit capable of producing firing temperature electrode heating, saidcircuit extending from one side of a voltage source to the opposite sideof said source and including in series connection said inductivereactance device, the first electrode, a preheating current limitingdevice, one set of relay contacts, the second electrode, said delaydevice operating circuit and a circuit connected in shunt with saidseries-connected relay operating coil and current controlling device,said shunt circuit including in series connection the contacts of saiddelay device and the second set of relay contacts so that the opening ofsaid delay contacts causes the energization of said relay operating coiland the consequent opening of said sets of relay contacts, the openingof said first set causing the discharge device to fire by an inductivevoltage kick, said first set of contacts being connected in shunt withsaid electrodes, and the opening of the second set of relay contactsmaintaining said operating coil energized after the delay devicecontacts have reclosed.

References Cited in the file of this patent UNITED STATES PATENTS2,046,980 Van Wijk July 7, 1936 2,266,616 Scott Dec. 16, 1941 2,291,355Simmon July 28, 1942 2,341,520 Babb Feb. 15, 1944 FOREIGN PATENTS530,828 Great Britain Dec. 22, 1940

